Use this calculation for a first-order acoustics estimate when the stated geometry, propagation model, averaging convention, reference quantity, and SI units match the measurement or design problem.

Room Cubic Meters

A finite measured or assumed value greater than or equal to 0, expressed in m3.

Total Surface Square Meters

A finite measured or assumed value greater than or equal to 0, expressed in m2.

The implemented rule is: Diffuse-field mean free path 4V/S inside a room from volume and total surface area.^[1]

Mean Free Path Meters

The calculated mean free path meters, expressed in m.

This is an idealized calculation rather than a complete acoustic simulation or measurement. Reflections, boundary conditions, directivity, damping, frequency dependence, near-field behavior, background noise, transducer response, temperature, humidity, and geometry can change a real result.

Confirm important results with calibrated measurements or a model that includes the actual geometry, materials, boundaries, source directivity, and frequency-dependent losses. Preserve the reference quantity and weighting whenever a result is expressed in decibels.

• Room Volume From Dimensions

  Rectangular room volume from internal length, width and height.

• Axial Mode Frequency

  Rectangular-room axial mode frequency along one dimension for a positive integer mode order.

• Oblique Mode Frequency

  Rectangular-room mode frequency for three nonzero axial orders and dimensions.